The purpose of my project is to examine the structure of human salivary mucins and relate this to their function. Mucins function as lubricants and protect host tissue from abrasion and dessication in the oral cavity. High and low molecular weight mucins (MG1 and MG2) have been isolated from human submandibular-sublingual gland saliva. MG1 has a molecular weight of > 1000 kDa and is ~80% carbohydrate. Very little is known about MG1 protein backbone structure. We have deglycosylated purified MG1 by hydrogen fluoride solvolysis and prepared a rabbit antisera to the protein fraction. The antisera was used to screen a human submandibular gland lambda gt11 cDNA library. Positive clones were purified, amplified by PCR, and subcloned into PGEM 11. Future studies will involve the sequencing of MG1 cDNA, identification of the MG1 gene, and examination of MG1 biosynthesis. A better understanding of mucin structure may help in design and production of synthetic mucins which will improve artificial salivas for xerostomia patients.